Organization of δ-crystallin genes in the chicken

Open Access
Publisher Website
Google Scholar
Abstract
Double-stranded DNA was synthesized from δ-crystallin mRNA prepared from lens fibers of 15-day-old chick embryos and cloned at the Pst I site of the plasmid pBR322. Using the cloned cDNA and single-stranded cDNA as hybridization probes, a number of genomic DNA fragments containing δ-crystallin gene sequences have been cloned from the partial and complete Eco RI digests of chick brain DNA. One of the clones from the partial digests contains a DNA fragment that consists of four Eco RI fragments of 7.6 kb, 4.0 kb, 2.6 kb, and 0.8 kb. The gene sequences reside in the (5′)7.6 kb-0.8 kb-4.0 kb(3′) fragments. Electron microscopy has provided evidence that the cloned DNA fragment includes the entire gene sequences complementary to δ-crystallin mRNA except for the 3′ terminal poly (A) tail, and that the δ-crystallin gene is interrupted by at least 13 intervening sequences. Another clone contains a genomic fragment that consists of two Eco RI fragments of 3.0 kb and 11 kb. The DNA fragment in the latter clone represents a different δ-crystallin gene, as judged by restriction endonuclease mapping and by electron microscopy.